50 trim, ported head, Greddy FMIC, dejon 3.5 intake..ect.....low vac???

[mustg5]

Alright ive heard that the more mods you have done to your car the lower your vac will be at idle......ive got a 50trim, ported and polished head, ross 8.5:1 pistons, eagle rods, dejon 3.5" intake tube, greddy FMIC, IC piping upper and lower, ported exhaust manifold, and 3" turbo back exhaust, alot of other mods......my question is, could this possible be causing my vac to be at 15hg at idle......ive heard yes and know, what do you think?

 

[jott5555]

15 is ok im at 18 i wouldnt be worried much, mabey do a boost leak test via vfaq.. http://www.vfaq.com/mods/ICtester.html

 

[GSntncT]

Alright ive heard that the more mods you have done to your car the lower your vac will be at idle......ive got a 50trim, ported and polished head, ross 8.5:1 pistons, eagle rods, dejon 3.5" intake tube, greddy FMIC, IC piping upper and lower, ported exhaust manifold, and 3" turbo back exhaust, alot of other mods......my question is, could this possible be causing my vac to be at 15hg at idle......ive heard yes and know, what do you think?

I would think it's possible. I was at 28 at idle with not much done. The more free flowing my engine became, the lower my vacuum was. Now, I'm around 16-18. I think your fine. Just do a leak test to be sure.

 

[crankbender]

Umm if your idle vacume is going down then you are flowing less air (assuming no leaks). This does not support the idea that a modified engine will pull less vacume (with the exception of cams which do flow less at idle).

It is very possible that you have managed to get a leak someplace. Pressurize your intake and see if it is ok.